ylipainutusta

Ylipainutus is a Finnish term that translates to overbanking or overstriking in English, and it refers to a process in the manufacturing of paper and paperboard. It is a stage in the papermaking process where the pulp slurry, which is a mixture of water and cellulose fibers, is spread onto a moving screen or wire. The term ylipainutus specifically relates to the method used to control the evenness and thickness of the paper sheet being formed.

In traditional papermaking, the pulp slurry flows from a headbox onto a wire mesh. The speed at which the wire moves and the consistency of the pulp slurry are crucial for creating a uniform sheet. Ylipainutus, in this context, can refer to techniques that ensure the pulp is distributed evenly across the width of the wire. This might involve using a slice lip on the headbox that precisely controls the flow and spread of the pulp, or other mechanical adjustments.

The goal of ylipainutus is to achieve a consistent basis weight and caliper (thickness) across the entire width of the paper or paperboard. Uneven distribution can lead to variations in strength, printability, and overall quality of the final product. Therefore, precise control during this stage is vital for producing high-quality paper products. The term is primarily used in the context of industrial papermaking machinery and processes.